1. Technical Field
The present technology relates to a heat-curable silicone resin composition for sealing optical semiconductors, and a sealed optical semiconductor using the same.
2. Related Art
Conventionally, epoxy resins have been proposed as resins for use in compositions for sealing optical semiconductors (e.g. Japanese Unexamined Patent Application Publication No. H10-228249A). However, there is a problem in that a color of seals formed from compositions including epoxy resin yellows due to heat emitted from white LED elements.
Additionally, organopolysiloxane compositions that cure at room temperature including an organopolysiloxane containing two silanol groups, a silane compound containing two or more hydrolyzable groups in the molecule that are bonded to a silicon atom, and an organic zirconium compound have been proposed (e.g. Japanese Unexamined Patent Application Publication No. 2001-200161A and Japanese Unexamined Patent Application Publication No. H02-196860A).
Moreover, mixing a condensation catalyst with a diorganopolysiloxane containing two silanol groups and a silane containing three or more alkoxy groups, and then heating the mixture has been proposed (e.g. Japanese Unexamined Patent Application Publication No. 2007-224089 and Japanese Unexamined Patent Application Publication No. 2006-206700).
However, gas permeability is higher when using a silicone resin compared to an epoxy resin and, thus, silver plating of optical semiconductor packages easily discolors over time due to the hydrogen sulfide in the air, which results in a tendency for brightness to decline.